The Australian parents of an Indian girl thought to have been kidnapped and sold to an adoption agency say they'll fight "tooth and claw" to keep her.

The Queensland couple, who cannot be named, legally adopted two girls from India in 2000.

It's since been revealed that one of them was kidnapped by criminals from near her home in a slum in Chennai in 1998 to be sold to a disreputable adoption agency.

Her birth mother, Fatima, now wants her back.

But her adoptive parents have sought legal advice and say they don't think the girl, now 17, should be forced to return to India.

"We will fight tooth and claw," her adoptive father told ABC television.

"We've been told that the chances of an Australian court ruling that an Australian citizen who's grown up here and has no memories of another country should be forced to go back there ... are almost non-existent.

"It almost certainly won't happen."

The adoptive father said he had been aware of the kidnapping allegations since about 2005, but had never received any conclusive evidence.

He said that when the allegations surfaced, he and his wife suggested allowing their daughter to stay with them until she was 18 and during that time keep the birth parents updated and, at a suitable time, allow contact.

"But we've never received a reply," he said.

"So our view is the ball is in their court."

Birth mother Fatima said as soon as a policeman told her and husband Salya in 2005 their child had been legally adopted to Australia, they had fought for her return.

She said she was told Australia was a good place and she shouldn't worry.

"But I told them that even if it is good, I want my child back," she said.

"They might have treated my child well but they should bring her back to meet us."

Fatima has taken her fight to the Australian government, arguing while the adoption may be legal in Australia, it began with a crime in India.